Within the field of cutting tools used in milling operations with high feed rates, there are many examples of generally square-shaped single-sided indexable cutting inserts having four primary or major cutting edges, in a top view of their top surface.
U.S. Pat. No. 6,945,740 in its FIGS. 4 to 8, discloses a single-sided indexable cutting insert having a generally square shape in a top view. The insert includes first and second pairs of mutually parallel primary (major) cutting edges, four corners, and four secondary (wiper) edges. Each wiper edge is situated between a major cutting edge and a respective corner. The wiper edges are shorter than the major cutting edges and are inclined relative thereto, wherein an imaginary extension line of the wiper edge forms a first acute angle with the respective major cutting edge as the insert is viewed in a direction perpendicular to the top surface. The cutting seats are arranged to orient the inserts wherein an axially forwardmost wiper edge of each insert lies in a plane oriented perpendicular to the axis, and wherein a radially outermost wiper edge of each insert is oriented parallel to the axis.
U.S. Pat. No. 7,220,083 in its FIGS. 4A to 4C, discloses a single-sided indexable cutting insert having a generally square shape in a top view. The insert has four identical convex cutting edges connected by nose corners. Each of the four convex cutting edges includes a curved primary (major) cutting edge portion with a large curvature radius, and two straight secondary (minor) cutting edge portions. The curved major cutting edge portions are said to provide the cutting insert with favorable cutting edge strength. A conical clearance surface extends downward from each major cutting edge portion, and a planar clearance surface extends downward from each minor cutting edge portion. A plurality of cutting insert are arranged in pockets of a cutting body such that a minor cutting edge portion of each insert is perpendicular to the cutting axis to guarantee good surface finish on the machined surface.
U.S. Pat. No. 4,681,488 in its FIGS. 2 to 4, discloses a single-sided indexable cutting insert having a generally square shape in a top view. In this insert, each of the corner cutting edges comprises a plurality of straight cutting edge segments.
U.S. Pat. No. 5,807,031 in its FIGS. 16 and 24, discloses a double-sided indexable cutting insert having a generally square shape in a top view. The insert has straight primary cutting edges, both ends of which form angles with adjacent straight cutting edge segments belonging to secondary and/or corner cutting edges.
US 2012/0070242A1 in its FIG. 25, discloses a single-sided indexable cutting insert having a generally square shape in a top view. The insert has straight primary cutting edges which form an angle with adjacent straight secondary cutting edge segments.
U.S. Pat. No. 6,957,935 in its FIGS. 2 to 4, discloses a single-sided indexable cutting insert having a generally square shape in a top view. The insert has curved primary cutting edges connecting with adjacent straight secondary cutting edges, each secondary cutting edge basically functioning as a wiper in square shoulder milling operations to improve surface finish of a workpiece.
US 2014/0341660A1 in its FIG. 7, discloses a double-sided indexable cutting insert having a generally square shape in a top view. The insert has straight primary cutting edges which form an angle of less than 180° with adjacent straight secondary cutting edges (“wiper edges”), the wiper edges basically functioning to improve surface finish of a workpiece in square shoulder milling operations.
It is an object of the present invention to provide an economically efficient indexable cutting insert suitable for use in milling operations with high feed rates.
It is also an object of the present invention to provide a robust cutting insert with prolonged service life.
It is further an object of the present invention to provide an improved rotary cutting tool in which the indexable cutting insert is removably secured in a cutting body with a high level of stability.